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membership_update_message.go
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membership_update_message.go
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package protocol
import (
"bytes"
"crypto/ecdsa"
"fmt"
"sort"
"strings"
"github.com/golang/protobuf/proto"
"github.com/google/uuid"
"github.com/pkg/errors"
"github.com/status-im/status-go/eth-node/crypto"
"github.com/status-im/status-go/eth-node/types"
"github.com/status-im/status-go/protocol/protobuf"
)
// MembershipUpdateMessage is a message used to propagate information
// about group membership changes.
// For more information, see https://github.com/status-im/specs/blob/master/status-group-chats-spec.md.
type MembershipUpdateMessage struct {
ChatID string `json:"chatId"` // UUID concatenated with hex-encoded public key of the creator for the chat
Events []MembershipUpdateEvent `json:"events"`
Message *protobuf.ChatMessage `json:"-"`
}
const signatureLength = 65
func MembershipUpdateEventFromProtobuf(chatID string, raw []byte) (*MembershipUpdateEvent, error) {
if len(raw) <= signatureLength {
return nil, errors.New("invalid payload length")
}
decodedEvent := protobuf.MembershipUpdateEvent{}
signature := raw[:signatureLength]
encodedEvent := raw[signatureLength:]
signatureMaterial := append([]byte(chatID), encodedEvent...)
publicKey, err := crypto.ExtractSignature(signatureMaterial, signature)
if err != nil {
return nil, errors.Wrap(err, "failed to extract signature")
}
from := types.EncodeHex(crypto.FromECDSAPub(publicKey))
err = proto.Unmarshal(encodedEvent, &decodedEvent)
if err != nil {
return nil, err
}
return &MembershipUpdateEvent{
ClockValue: decodedEvent.Clock,
ChatID: chatID,
Members: decodedEvent.Members,
Name: decodedEvent.Name,
Type: decodedEvent.Type,
Signature: signature,
RawPayload: encodedEvent,
From: from,
}, nil
}
func (m *MembershipUpdateMessage) ToProtobuf() *protobuf.MembershipUpdateMessage {
var rawEvents [][]byte
for _, e := range m.Events {
var encodedEvent []byte
encodedEvent = append(encodedEvent, e.Signature...)
encodedEvent = append(encodedEvent, e.RawPayload...)
rawEvents = append(rawEvents, encodedEvent)
}
return &protobuf.MembershipUpdateMessage{
ChatId: m.ChatID,
Events: rawEvents,
Message: m.Message,
}
}
func MembershipUpdateMessageFromProtobuf(raw *protobuf.MembershipUpdateMessage) (*MembershipUpdateMessage, error) {
var events []MembershipUpdateEvent
for _, e := range raw.Events {
verifiedEvent, err := MembershipUpdateEventFromProtobuf(raw.ChatId, e)
if err != nil {
return nil, err
}
events = append(events, *verifiedEvent)
}
return &MembershipUpdateMessage{
ChatID: raw.ChatId,
Events: events,
Message: raw.Message,
}, nil
}
// EncodeMembershipUpdateMessage encodes a MembershipUpdateMessage using protobuf serialization.
func EncodeMembershipUpdateMessage(value MembershipUpdateMessage) ([]byte, error) {
return proto.Marshal(value.ToProtobuf())
}
// MembershipUpdateEvent contains an event information.
// Member and Members are hex-encoded values with 0x prefix.
type MembershipUpdateEvent struct {
Type protobuf.MembershipUpdateEvent_EventType `json:"type"`
ClockValue uint64 `json:"clockValue"`
Members []string `json:"members,omitempty"` // in "members-added" and "admins-added" events
Name string `json:"name,omitempty"` // name of the group chat
From string `json:"from,omitempty"`
Signature []byte `json:"signature,omitempty"`
ChatID string `json:"chatId"`
RawPayload []byte `json:"rawPayload"`
}
func (u *MembershipUpdateEvent) Equal(update MembershipUpdateEvent) bool {
return bytes.Equal(u.Signature, update.Signature)
}
func (u *MembershipUpdateEvent) Sign(key *ecdsa.PrivateKey) error {
if len(u.ChatID) == 0 {
return errors.New("can't sign with empty chatID")
}
encodedEvent, err := proto.Marshal(u.ToProtobuf())
if err != nil {
return err
}
u.RawPayload = encodedEvent
var signatureMaterial []byte
signatureMaterial = append(signatureMaterial, []byte(u.ChatID)...)
signatureMaterial = crypto.Keccak256(append(signatureMaterial, u.RawPayload...))
signature, err := crypto.Sign(signatureMaterial, key)
if err != nil {
return err
}
u.Signature = signature
u.From = types.EncodeHex(crypto.FromECDSAPub(&key.PublicKey))
return nil
}
func (u *MembershipUpdateEvent) ToProtobuf() *protobuf.MembershipUpdateEvent {
return &protobuf.MembershipUpdateEvent{
Clock: u.ClockValue,
Name: u.Name,
Members: u.Members,
Type: u.Type,
}
}
func MergeMembershipUpdateEvents(dest []MembershipUpdateEvent, src []MembershipUpdateEvent) []MembershipUpdateEvent {
for _, update := range src {
var exists bool
for _, existing := range dest {
if existing.Equal(update) {
exists = true
break
}
}
if !exists {
dest = append(dest, update)
}
}
return dest
}
func NewChatCreatedEvent(name string, clock uint64) MembershipUpdateEvent {
return MembershipUpdateEvent{
Type: protobuf.MembershipUpdateEvent_CHAT_CREATED,
Name: name,
ClockValue: clock,
}
}
func NewNameChangedEvent(name string, clock uint64) MembershipUpdateEvent {
return MembershipUpdateEvent{
Type: protobuf.MembershipUpdateEvent_NAME_CHANGED,
Name: name,
ClockValue: clock,
}
}
func NewMembersAddedEvent(members []string, clock uint64) MembershipUpdateEvent {
return MembershipUpdateEvent{
Type: protobuf.MembershipUpdateEvent_MEMBERS_ADDED,
Members: members,
ClockValue: clock,
}
}
func NewMemberJoinedEvent(clock uint64) MembershipUpdateEvent {
return MembershipUpdateEvent{
Type: protobuf.MembershipUpdateEvent_MEMBER_JOINED,
ClockValue: clock,
}
}
func NewAdminsAddedEvent(admins []string, clock uint64) MembershipUpdateEvent {
return MembershipUpdateEvent{
Type: protobuf.MembershipUpdateEvent_ADMINS_ADDED,
Members: admins,
ClockValue: clock,
}
}
func NewMemberRemovedEvent(member string, clock uint64) MembershipUpdateEvent {
return MembershipUpdateEvent{
Type: protobuf.MembershipUpdateEvent_MEMBER_REMOVED,
Members: []string{member},
ClockValue: clock,
}
}
func NewAdminRemovedEvent(admin string, clock uint64) MembershipUpdateEvent {
return MembershipUpdateEvent{
Type: protobuf.MembershipUpdateEvent_ADMIN_REMOVED,
Members: []string{admin},
ClockValue: clock,
}
}
type Group struct {
chatID string
name string
events []MembershipUpdateEvent
admins *stringSet
members *stringSet
joined *stringSet
}
func groupChatID(creator *ecdsa.PublicKey) string {
return uuid.New().String() + "-" + types.EncodeHex(crypto.FromECDSAPub(creator))
}
func NewGroupWithEvents(chatID string, events []MembershipUpdateEvent) (*Group, error) {
return newGroup(chatID, events)
}
func NewGroupWithCreator(name string, clock uint64, creator *ecdsa.PrivateKey) (*Group, error) {
chatID := groupChatID(&creator.PublicKey)
chatCreated := NewChatCreatedEvent(name, clock)
chatCreated.ChatID = chatID
err := chatCreated.Sign(creator)
if err != nil {
return nil, err
}
return newGroup(chatID, []MembershipUpdateEvent{chatCreated})
}
func newGroup(chatID string, events []MembershipUpdateEvent) (*Group, error) {
g := Group{
chatID: chatID,
events: events,
admins: newStringSet(),
members: newStringSet(),
joined: newStringSet(),
}
if err := g.init(); err != nil {
return nil, err
}
return &g, nil
}
func (g *Group) init() error {
g.sortEvents()
var chatID string
for _, event := range g.events {
if chatID == "" {
chatID = event.ChatID
} else if event.ChatID != chatID {
return errors.New("updates contain different chat IDs")
}
valid := g.validateEvent(event)
if !valid {
return fmt.Errorf("invalid event %#+v from %s", event, event.From)
}
g.processEvent(event)
}
valid := g.validateChatID(g.chatID)
if !valid {
return fmt.Errorf("invalid chat ID: %s", g.chatID)
}
if chatID != g.chatID {
return fmt.Errorf("expected chat ID equal %s, got %s", g.chatID, chatID)
}
return nil
}
func (g Group) ChatID() string {
return g.chatID
}
func (g Group) Name() string {
return g.name
}
func (g Group) Events() []MembershipUpdateEvent {
return g.events
}
func (g Group) Members() []string {
return g.members.List()
}
func (g Group) Admins() []string {
return g.admins.List()
}
func (g Group) Joined() []string {
return g.joined.List()
}
func (g *Group) ProcessEvents(events []MembershipUpdateEvent) error {
for _, event := range events {
err := g.ProcessEvent(event)
if err != nil {
return err
}
}
return nil
}
func (g *Group) ProcessEvent(event MembershipUpdateEvent) error {
if !g.validateEvent(event) {
return fmt.Errorf("invalid event %#+v", event)
}
// Check if exists
g.events = append(g.events, event)
g.processEvent(event)
return nil
}
func (g Group) LastClockValue() uint64 {
if len(g.events) == 0 {
return 0
}
return g.events[len(g.events)-1].ClockValue
}
func (g Group) creator() (string, error) {
if len(g.events) == 0 {
return "", errors.New("no events in the group")
}
first := g.events[0]
if first.Type != protobuf.MembershipUpdateEvent_CHAT_CREATED {
return "", fmt.Errorf("expected first event to be 'chat-created', got %s", first.Type)
}
return first.From, nil
}
func (g Group) validateChatID(chatID string) bool {
creator, err := g.creator()
if err != nil || creator == "" {
return false
}
// TODO: It does not verify that the prefix is a valid UUID.
// Improve it so that the prefix follows UUIDv4 spec.
return strings.HasSuffix(chatID, creator) && chatID != creator
}
func (g Group) IsMember(id string) bool {
return g.members.Has(id)
}
// validateEvent returns true if a given event is valid.
func (g Group) validateEvent(event MembershipUpdateEvent) bool {
if len(event.From) == 0 {
return false
}
switch event.Type {
case protobuf.MembershipUpdateEvent_CHAT_CREATED:
return g.admins.Empty() && g.members.Empty()
case protobuf.MembershipUpdateEvent_NAME_CHANGED:
return g.admins.Has(event.From) && len(event.Name) > 0
case protobuf.MembershipUpdateEvent_MEMBERS_ADDED:
return g.admins.Has(event.From)
case protobuf.MembershipUpdateEvent_MEMBER_JOINED:
return g.members.Has(event.From)
case protobuf.MembershipUpdateEvent_MEMBER_REMOVED:
// Member can remove themselves or admin can remove a member.
return len(event.Members) == 1 && (event.From == event.Members[0] || (g.admins.Has(event.From) && !g.admins.Has(event.Members[0])))
case protobuf.MembershipUpdateEvent_ADMINS_ADDED:
return g.admins.Has(event.From) && stringSliceSubset(event.Members, g.members.List())
case protobuf.MembershipUpdateEvent_ADMIN_REMOVED:
return len(event.Members) == 1 && g.admins.Has(event.From) && event.From == event.Members[0]
default:
return false
}
}
func (g *Group) processEvent(event MembershipUpdateEvent) {
switch event.Type {
case protobuf.MembershipUpdateEvent_CHAT_CREATED:
g.name = event.Name
g.members.Add(event.From)
g.joined.Add(event.From)
g.admins.Add(event.From)
case protobuf.MembershipUpdateEvent_NAME_CHANGED:
g.name = event.Name
case protobuf.MembershipUpdateEvent_ADMINS_ADDED:
g.admins.Add(event.Members...)
case protobuf.MembershipUpdateEvent_ADMIN_REMOVED:
g.admins.Remove(event.Members[0])
case protobuf.MembershipUpdateEvent_MEMBERS_ADDED:
g.members.Add(event.Members...)
case protobuf.MembershipUpdateEvent_MEMBER_REMOVED:
g.admins.Remove(event.Members[0])
g.joined.Remove(event.Members[0])
g.members.Remove(event.Members[0])
case protobuf.MembershipUpdateEvent_MEMBER_JOINED:
g.joined.Add(event.From)
}
}
func (g *Group) sortEvents() {
sort.Slice(g.events, func(i, j int) bool {
return g.events[i].ClockValue < g.events[j].ClockValue
})
}
func stringSliceSubset(subset []string, set []string) bool {
for _, item1 := range set {
var found bool
for _, item2 := range subset {
if item1 == item2 {
found = true
break
}
}
if found {
return true
}
}
return false
}
func publicKeyToString(publicKey *ecdsa.PublicKey) string {
return types.EncodeHex(crypto.FromECDSAPub(publicKey))
}
type stringSet struct {
m map[string]struct{}
items []string
}
func newStringSet() *stringSet {
return &stringSet{
m: make(map[string]struct{}),
}
}
func newStringSetFromSlice(s []string) *stringSet {
set := newStringSet()
if len(s) > 0 {
set.Add(s...)
}
return set
}
func (s *stringSet) Add(items ...string) {
for _, item := range items {
if _, ok := s.m[item]; !ok {
s.m[item] = struct{}{}
s.items = append(s.items, item)
}
}
}
func (s *stringSet) Remove(items ...string) {
for _, item := range items {
if _, ok := s.m[item]; ok {
delete(s.m, item)
s.removeFromItems(item)
}
}
}
func (s *stringSet) Has(item string) bool {
_, ok := s.m[item]
return ok
}
func (s *stringSet) Empty() bool {
return len(s.items) == 0
}
func (s *stringSet) List() []string {
return s.items
}
func (s *stringSet) removeFromItems(dropped string) {
n := 0
for _, item := range s.items {
if item != dropped {
s.items[n] = item
n++
}
}
s.items = s.items[:n]
}